1. Field of the Invention
The present invention relates generally to transport devices for loading, transporting and unloading containers and, specifically, to a transport trailer used to transport a pair containers, such as refuse containers, over a roadway.
2. Description of the Prior Art
A variety of trailer devices are known in the prior art for loading, transporting and unloading refuse and recycling type containers. These refuse and recycling containers, referred to collectively herein as xe2x80x9crefusexe2x80x9d containers, are typically steel boxes with or without tops. The containers are sometimes lifted from, e.g., a site adjacent a retail store, for loading onto a truck for transport to a dump or recycling location.
Other known transport devices used in the industry include trailers which are used for transporting removable containers between job sites, storage terminals, dumping sites and the like. The trailers are towed by tractors and are equipped with hydraulic or electrical systems for loading, unloading or otherwise handling the containers. For example, an empty refuse container might be transported from a storage terminal to a job location where the container is left behind for the collection of refuse. A full container might be loaded and transported to a dumping site or back to a storage terminal. The present invention is directed to the trailer type transport device used for transporting containers.
Trailers of the above type are typically provided with an undercarriage carrying a tilt frame. The tilt frame is movable between a horizontal position for transport and a tilted or inclined position for loading, unloading and/or dumping the container contents. In the inclined position, the tilt frame defines a ramp onto which a container resting on the ground can be hoisted. When the tilt frame is lowered back to its level position, the trailer can be used to transport the container over, e.g., a roadway. To unload the container from the trailer, the tilt frame is tilted again to allow the container to slide down the inclined surface of the tilt frame onto a surrounding substrate. The unloading operation is typically accomplished through the use of a taut cable and winch arrangement or similar devices.
The above general discussion describes the operation of a trailer designed to accommodate a single container. In some situations, trailers are provided for accommodating double container loads. In such situations, only the rear trailer needs to be tiltable for loading, unloading and/or dumping. The double container trailer thus has a front half which defines a front rest position and a rear half which defines a rear rest position. Mechanisms are provided for moving a container forward and backward between the front and rear rest positions when the tilt frame is in the horizontal position.
In the operation of a typical double container trailer, the tilt frame is first inclined. A cable is attached to a first container. The first container is pulled up the inclined tilt frame by hydraulic cylinders or a winch attached to the cable. The tilt frame is then lowered to the horizontal position. The first container is moved forward into the front rest position, clear of the tilt frame, which can be tilted again to pull up the second container. The second container is loaded in the same fashion using the same pulling apparatus, but is not moved any farther forward than a rear docking position on the tilt frame.
When two containers are being transported, the front container will need to be moved forward and backward to clear the tilt frame. This necessarily complicates the driving structure needed. The existing devices use various mechanical means for moving the first container between the front and rear rest positions on the trailer main frame. The known devices may employ as many as three driving systems, each with an independent cable arrangement mounted at a different point on the trailer and terminating in a connector end attachable to one or the other of the containers.
The prior art devices have tended to be overly complicated in design and manufacture due to the fact that one trailer must tilt while the other is stationary, due to the different directions in which the force must be applied, and the different endpoints from which force must be applied. As a result, the operator was required to accomplish the attachment, detachment and stowing of multiple cables. The prior art designs also featured complicated multiple winch and trolley arrangements which were cumbersome in design and difficult to operate and maintain.
One object of this invention is to provide a double container trailer which does not require the number of steps in attaching and detaching cables as was required in the prior art devices.
Another object of the invention is to provide such a double container system which does not require the number of winches and trolleys required in the prior art devices.
Another object of the invention is to provide such an apparatus which is simple in design and economical to manufacture, which is safe and reliable in operation, which conserves the operator""s time during the loading and unloading operation.
The double container trailer of the invention has a main trailer frame including a front trailer frame and a rear trailer frame, both of which define a top support surface. The rear trailer frame also includes a tilt frame pivotally mounted thereon for supporting a first load bearing container. Pivot means operatively connected between the rear trailer frame and the tilt frame are used to pivot the tilt frame and its associated container about a pivot point located on the rear trailer frame. A primary cable drive means is located on the rear trailer frame and has an engagement member for engaging a first load bearing container and transporting the first container onto the top support surface of the main trailer frame to an initial transport position. A secondary cable drive means operatively associated with the front trailer frame has an engagement member for engaging the first load bearing container and transporting the first load bearing container onto the top support surface of the main trailer frame to a final transport position forward of the initial transport position.
The pivot means comprises at least one hydraulic cylinder of the type having an associated output shaft, a selected one of the cylinder and shaft being connected to the trailer main trailer frame, the other of the cylinder and shaft being connected to the tilt frame for pivoting the tilt frame and its associated container about the pivot point located on the rear trailer frame. The primary cable drive means includes at least one hydraulic cylinder and an associated cable, actuation of the hydraulic cylinder serving to move the associated cable and engagement member to move an associated load bearing container. The secondary drive means includes a winch drum having a threaded external surface which defines a series of thread grooves and a forward cable, the forward cable being wound onto the threaded external surface of the winch drum and extending in either of opposite directions between spaced sheaves located on the trailer main frame. The engagement member is carried by the forward cable and is movable backward and forward between the spaced sheaves by actuation of the winch drum. Preferably, the external surface of the winch drum is threaded as a continuous a screw profile.
In the method of the invention, a load bearing container is moved to the initial transport position by engaging the container with the engagement member of the primary cable drive means and actuating the primary cable drive means. The load bearing container is moved to the final transport position by engaging the container with the engagement member of the secondary cable drive means. A second load bearing container is then placed on the support surface of the main trailer frame. The load bearing container is moved to the initial transport position by engaging the container with the engagement member of the primary cable drive means and actuating the primary cable drive means. The secondary drive means includes a winch drum having a threaded external surface which defines a series of thread grooves and a forward cable, the forward cable being wound onto the threaded external surface of the winch drum and extending in either of opposite directions between spaced sheaves located on the trailer main frame, the engagement member being carried by the forward cable and being movable backward and forward between the spaced sheaves by actuation of the winch drum.
Additional objects, features and advantages will be apparent in the written description which follows.